1. Field of the Invention
The present invention relates generally to an apparatus and method for setting a neighbor in a mobile communication system.
2. Description of the Related Art
Currently, wireless data services such as Code Division Multiple Access (CDMA) 2000, Evolution Data Only (EV-DO), Wideband CDMA (WCDMA), and Wireless Local Area Network (WLAN) have been commercially available; moreover, use of a portable phone and demand for mobile data has been continuously increased at home. According to such a trend, a method has been proposed for providing a mobile communication service by using a subminiature Node B in a building in order to access a mobile communication core network through an indoor broadband network.
For example, in a next-generation network system, a method has been proposed in which a plurality of multi-cells with a small size, for example, femto cells, are arranged in order to satisfy needs for a high data transmission rate and to stably provide various services. A subminiature Node B managing such a femto cell is referred to as an indoor Node B or a femto Node B. By reducing a size of the cell, efficiency of the next-generation network system using a high frequency band will be improved, and use of several cells with the small size is advantageous in view of increasing times of reusing a frequency. Further, a service scheme using the multi-cells with the small size has an advantage in that deterioration of a channel condition due to a reduction of electric waves occurring when one conventional Node B covers all cell area and service impossibility for a user in a shadow area can be solved. Based on such advantages, a combination scheme of a conventional macro cell, i.e., a cell area which an outdoor Node B manages, and femto cells, i.e., a cell area which a subminiature Node B such as an indoor Node B and a femto Node B manages, has appeared.
A Long Term Evolution (LTE) system is a network capable of satisfying needs for a high data rate for an access network, low latency, and packet optimized radio access. The LTE system secures backward compatibility with an access network of a conventional 3GPP/non-3GPP while receiving a high rate rich media. The LTE system is an all-IP based network excluding a conventional circuit-switched communication, which enhances a Quality of Service (QoS) management function and provides a discriminate QoS for a real-time service, e.g., voice communication and video communication, and a non-real-time service, e.g., web browsing and stored and forwarded data transmission, so as to improve efficiency of network resources. Further, the LTE system has introduced a smart antenna technology, i.e. Multiple Input Multiple Output (MIMO), and has expanded a bandwidth for wireless communication.
A setting of a neighbor in a mobile communication system which does not include an automatic optimization technology, such as Self Organizing Networks (SON), is achieved by an operator based on location information of a Node B. In an improved neighbor optimization method, call fault data, handover statistic data, Primary Scrambling Code (PSC) information in each sector, and the like as well as the location information of the Node B, etc., may be used.
In the mobile communication system, coverage of a cell is affected by many factors such as a location of a radio unit, a direction of an antenna, interference with another cell, and the like. Therefore, if a neighbor optimization is performed by reference of only the location information of the Node B, the actual coverage of the cell may not be identical to the neighbor setting. When a User Equipment (UE) moves between two adjacent cells in which the neighbor is not set, it is impossible to perform a handover process while maintaining the continuity of a call. Thus, a call drop occurs or a cutoff of user traffic occurs due to a performance of Radio Resource Control (RRC) Re-establishment (RRE), thereby deteriorating a quality of a corresponding system.